Many communication switch and router systems architectures provide redundant communications capabilities. Redundancy in a router system can be provided on two levels A first level provides redundancy within a single shelf for a communications switch. Therein, two or more modules provide redundant communications capabilities for another communication module on the same shelf. A second type of redundancy provides fabric redundancy beyond the switch matrix (SMX) cards and includes fabric interface cards (FICs) installed on input/output (I/O) shelves, high-speed inter-shelf links (HISLs), cables connecting I/O shelves and switch access cards (SACs) installed in switching shelves.
Prior art designs exhibit some inherent limitations. For example, in certain prior art designs, the redundant fabrics may be interconnected and may co-depend on each other to effect an activity switch between the fabrics. This co-dependency between the redundant fabrics may be problematic, depending on the type of fault that is initiating the activity switch between the fabrics. Furthermore, in prior art designs, the time it takes to execute an activity switch between redundant fabrics may be in the order of several seconds or more, which may not comply with industry standards for certain switching applications.
For routing switch platforms used for telecommunications applications, for example, the current Bellcore standard GR-1110-CORE mandates that an activity switch must be completed within 60 ms upon detection of a first fault in any switching fabric. Many prior art designs do not meet this Bellcore standard for an activity switch upon a first fault.
Accordingly, there is a need for an improved system for providing fabric redundancy and executing a fabric activity switch which overcomes the limitations in the prior art, and which meets or exceeds industry standards such as Bellcore standard GR-1110-CORE.